[PATCH v14 19/26] crypto: iaa - Enable async mode and make it the default.

[Kanchana P Sridhar <kanchana.p.sridhar@intel.com>]

This patch enables the 'async' sync_mode in the driver. Further, it sets
the default sync_mode to 'async', which makes it easier for IAA hardware
acceleration in the iaa_crypto driver to be loaded by default in the most
efficient/recommended 'async' mode for parallel
compressions/decompressions, namely, asynchronous submission of
descriptors, followed by polling for job completions. Earlier, the
"sync" mode used to be the default.

The iaa_crypto driver documentation has been updated with these
changes.

This way, anyone who wants to use IAA as a zswap compressor, can do so
right after building the kernel. Specifically, they *do not* have to go
through these steps to use async mode:

  1) disable all the IAA device/wq bindings that happen at boot time
  2) rmmod iaa_crypto
  3) modprobe iaa_crypto
  4) echo async > /sys/bus/dsa/drivers/crypto/sync_mode
  5) re-run initialization of the IAA devices and wqs

Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
---
 Documentation/driver-api/crypto/iaa/iaa-crypto.rst | 11 ++---------
 drivers/crypto/intel/iaa/iaa_crypto_main.c         |  4 ++--
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/Documentation/driver-api/crypto/iaa/iaa-crypto.rst b/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
index 0ff4ec603b43..d5e610ef4612 100644
--- a/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
+++ b/Documentation/driver-api/crypto/iaa/iaa-crypto.rst
@@ -272,7 +272,7 @@ The available attributes are:
       echo async_irq > /sys/bus/dsa/drivers/crypto/sync_mode
 
     Async mode without interrupts (caller must poll) can be enabled by
-    writing 'async' to it (please see Caveat)::
+    writing 'async' to it::
 
       echo async > /sys/bus/dsa/drivers/crypto/sync_mode
 
@@ -281,14 +281,7 @@ The available attributes are:
 
       echo sync > /sys/bus/dsa/drivers/crypto/sync_mode
 
-    The default mode is 'sync'.
-
-    Caveat: since the only mechanism that iaa_crypto currently implements
-    for async polling without interrupts is via the 'sync' mode as
-    described earlier, writing 'async' to
-    '/sys/bus/dsa/drivers/crypto/sync_mode' will internally enable the
-    'sync' mode. This is to ensure correct iaa_crypto behavior until true
-    async polling without interrupts is enabled in iaa_crypto.
+    The default mode is 'async'.
 
   - g_comp_wqs_per_iaa
 
diff --git a/drivers/crypto/intel/iaa/iaa_crypto_main.c b/drivers/crypto/intel/iaa/iaa_crypto_main.c
index 915bf9b17b39..f6e18f458fbf 100644
--- a/drivers/crypto/intel/iaa/iaa_crypto_main.c
+++ b/drivers/crypto/intel/iaa/iaa_crypto_main.c
@@ -153,7 +153,7 @@ static bool iaa_verify_compress = true;
  */
 
 /* Use async mode */
-static bool async_mode;
+static bool async_mode = true;
 /* Use interrupts */
 static bool use_irq;
 
@@ -207,7 +207,7 @@ static int set_iaa_sync_mode(const char *name)
 		async_mode = false;
 		use_irq = false;
 	} else if (sysfs_streq(name, "async")) {
-		async_mode = false;
+		async_mode = true;
 		use_irq = false;
 	} else if (sysfs_streq(name, "async_irq")) {
 		async_mode = true;
-- 
2.27.0